Impulse Calculator
Calculate impulse using J = F × t, where force is in newtons and time in seconds. Impulse equals the change in momentum of an object and is essential in collision analysis and sports science.
How to use this tool
- Enter force and time in the fields above.
- Results update instantly as you type — or click Calculate.
- Read your impulse and the full breakdown beneath it.
Formula
J = F * t
How it works
Impulse J is the product of the net force F (N) applied over a time interval t (s). By the impulse-momentum theorem, J = Δp.
Worked examples
Kicking a ball
Gravity over 3 s
Common mistakes to avoid
- Using average force when the force varies over time — J = F*t is valid only for a constant force; for variable force you need J = integral of F dt.
- Confusing impulse J (N s) with momentum p (also N s) — impulse is the change in momentum, not the momentum itself.
- Entering time in milliseconds without converting to seconds, making the calculated impulse 1000 times too small.
Key terms
Frequently asked questions
- What is the impulse-momentum theorem?
- The impulse-momentum theorem states that the impulse acting on an object equals its change in momentum: J = delta_p = m*(v_final - v_initial). This connects force and time to changes in motion.
- Why is impulse important in sports science?
- In sports like cricket or baseball, a bat applies a large force over a very short contact time. Impulse (F * t) determines how much the ball's momentum changes. Increasing contact time (following through) at the same average force increases impulse and ball speed.
- Can I use this calculator if I know the change in velocity instead of the force and time?
- Not directly — this calculator uses J = F * t. To find impulse from mass and velocity change, compute delta_p = m * delta_v directly; that equals the impulse by the impulse-momentum theorem.